+#include "access_rx_cache.h"
+#include "complete_pread.h"
#include "db.h"
+#include "dprintf.h"
#include "io_uring_engine.h"
-#include "vp4.h"
+#include "needle.h"
+#include "parse_trigrams.h"
+#include "serializer.h"
+#include "turbopfor.h"
+#include "unique_sort.h"
#include <algorithm>
-#include <arpa/inet.h>
+#include <assert.h>
+#include <atomic>
#include <chrono>
-#include <endian.h>
+#include <condition_variable>
+#include <deque>
#include <fcntl.h>
#include <functional>
#include <getopt.h>
+#include <inttypes.h>
+#include <iterator>
+#include <limits>
+#include <locale.h>
#include <memory>
+#include <mutex>
+#include <regex.h>
+#include <stdint.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
#include <string>
+#include <string_view>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <thread>
+#include <tuple>
#include <unistd.h>
#include <unordered_map>
+#include <unordered_set>
+#include <utility>
#include <vector>
#include <zstd.h>
using namespace std;
using namespace std::chrono;
-#define dprintf(...)
-//#define dprintf(...) fprintf(stderr, __VA_ARGS__);
-
-const char *dbpath = "/var/lib/mlocate/plocate.db";
+bool ignore_case = false;
+bool only_count = false;
bool print_nul = false;
-
-class Serializer {
-public:
- void do_or_wait(int seq, function<void()> cb);
-
-private:
- int next_seq = 0;
- struct Element {
- int seq;
- function<void()> cb;
-
- bool operator<(const Element &other) const
- {
- return seq > other.seq;
- }
- };
- priority_queue<Element> pending;
-};
-
-void Serializer::do_or_wait(int seq, function<void()> cb)
-{
- if (seq != next_seq) {
- pending.emplace(Element{ seq, move(cb) });
- return;
- }
-
- cb();
- ++next_seq;
-
- while (!pending.empty() && pending.top().seq == next_seq) {
- pending.top().cb();
- pending.pop();
- ++next_seq;
- }
-}
-
-static inline uint32_t read_unigram(const string &s, size_t idx)
-{
- if (idx < s.size()) {
- return (unsigned char)s[idx];
- } else {
- return 0;
- }
-}
-
-static inline uint32_t read_trigram(const string &s, size_t start)
-{
- return read_unigram(s, start) | (read_unigram(s, start + 1) << 8) |
- (read_unigram(s, start + 2) << 16);
-}
-
-bool has_access(const char *filename,
- unordered_map<string, bool> *access_rx_cache)
-{
- const char *end = strchr(filename + 1, '/');
- while (end != nullptr) {
- string parent_path(filename, end);
- auto it = access_rx_cache->find(parent_path);
- bool ok;
- if (it == access_rx_cache->end()) {
- ok = access(parent_path.c_str(), R_OK | X_OK) == 0;
- access_rx_cache->emplace(move(parent_path), ok);
- } else {
- ok = it->second;
- }
- if (!ok) {
- return false;
- }
- end = strchr(end + 1, '/');
- }
-
- return true;
-}
+bool use_debug = false;
+bool flush_cache = false;
+bool patterns_are_regex = false;
+bool use_extended_regex = false;
+bool match_basename = false;
+bool check_existence = false;
+bool ignore_visibility = false;
+int64_t limit_matches = numeric_limits<int64_t>::max();
+int64_t limit_left = numeric_limits<int64_t>::max();
+bool stdout_is_tty = false;
+bool literal_printing = false;
+static bool in_forked_child = false;
+
+steady_clock::time_point start;
+ZSTD_DDict *ddict = nullptr;
class Corpus {
public:
- Corpus(int fd, IOUringEngine *engine);
+ Corpus(int fd, const char *filename_for_errors, IOUringEngine *engine);
~Corpus();
void find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb);
- void get_compressed_filename_block(uint32_t docid, function<void(string)> cb) const;
+ void get_compressed_filename_block(uint32_t docid, function<void(string_view)> cb) const;
size_t get_num_filename_blocks() const;
off_t offset_for_block(uint32_t docid) const
{
return hdr.filename_index_offset_bytes + docid * sizeof(uint64_t);
}
+ const Header &get_hdr() const { return hdr; }
public:
const int fd;
Header hdr;
};
-Corpus::Corpus(int fd, IOUringEngine *engine)
+Corpus::Corpus(int fd, const char *filename_for_errors, IOUringEngine *engine)
: fd(fd), engine(engine)
{
- // Enable to test cold-cache behavior (except for access()).
- if (false) {
+ if (flush_cache) {
off_t len = lseek(fd, 0, SEEK_END);
if (len == -1) {
perror("lseek");
complete_pread(fd, &hdr, sizeof(hdr), /*offset=*/0);
if (memcmp(hdr.magic, "\0plocate", 8) != 0) {
- fprintf(stderr, "plocate.db is corrupt or an old version; please rebuild it.\n");
+ fprintf(stderr, "%s: database is corrupt or not a plocate database; please rebuild it.\n", filename_for_errors);
exit(1);
}
- if (hdr.version != 0) {
- fprintf(stderr, "plocate.db has version %u, expected 0; please rebuild it.\n", hdr.version);
+ if (hdr.version != 0 && hdr.version != 1) {
+ fprintf(stderr, "%s: has version %u, expected 0 or 1; please rebuild it.\n", filename_for_errors, hdr.version);
exit(1);
}
+ if (hdr.version == 0) {
+ // These will be junk data.
+ hdr.zstd_dictionary_offset_bytes = 0;
+ hdr.zstd_dictionary_length_bytes = 0;
+ }
+ if (hdr.max_version < 2) {
+ // This too. (We ignore the other max_version 2 fields.)
+ hdr.check_visibility = true;
+ }
+ if (ignore_visibility) {
+ hdr.check_visibility = false;
+ }
}
Corpus::~Corpus()
void Corpus::find_trigram(uint32_t trgm, function<void(const Trigram *trgmptr, size_t len)> cb)
{
uint32_t bucket = hash_trigram(trgm, hdr.hashtable_size);
- engine->submit_read(fd, sizeof(Trigram) * (hdr.extra_ht_slots + 2), hdr.hash_table_offset_bytes + sizeof(Trigram) * bucket, [this, trgm, bucket, cb{ move(cb) }](string s) {
+ engine->submit_read(fd, sizeof(Trigram) * (hdr.extra_ht_slots + 2), hdr.hash_table_offset_bytes + sizeof(Trigram) * bucket, [this, trgm, cb{ move(cb) }](string_view s) {
const Trigram *trgmptr = reinterpret_cast<const Trigram *>(s.data());
for (unsigned i = 0; i < hdr.extra_ht_slots + 1; ++i) {
if (trgmptr[i].trgm == trgm) {
});
}
-void Corpus::get_compressed_filename_block(uint32_t docid, function<void(string)> cb) const
+void Corpus::get_compressed_filename_block(uint32_t docid, function<void(string_view)> cb) const
{
// Read the file offset from this docid and the next one.
// This is always allowed, since we have a sentinel block at the end.
- engine->submit_read(fd, sizeof(uint64_t) * 2, offset_for_block(docid), [this, cb{ move(cb) }](string s) {
+ engine->submit_read(fd, sizeof(uint64_t) * 2, offset_for_block(docid), [this, cb{ move(cb) }](string_view s) {
const uint64_t *ptr = reinterpret_cast<const uint64_t *>(s.data());
off_t offset = ptr[0];
size_t len = ptr[1] - ptr[0];
size_t Corpus::get_num_filename_blocks() const
{
- // The beginning of the filename blocks is the end of the filename index blocks.
- uint64_t end;
- complete_pread(fd, &end, sizeof(end), hdr.filename_index_offset_bytes);
-
- // Subtract the sentinel block.
- return (end - hdr.filename_index_offset_bytes) / sizeof(uint64_t) - 1;
+ return hdr.num_docids;
}
-size_t scan_file_block(const vector<string> &needles, string_view compressed,
- unordered_map<string, bool> *access_rx_cache)
+template<class T>
+void stat_if_needed(const char *filename, bool access_ok, IOUringEngine *engine, T cb)
{
- size_t matched = 0;
+ if (!access_ok || !check_existence) {
+ // Doesn't have access or doesn't care about existence, so no need to stat.
+ cb(access_ok);
+ } else if (engine == nullptr || !engine->get_supports_stat()) {
+ // Do a synchronous stat.
+ struct stat buf;
+ bool ok = lstat(filename, &buf) == 0;
+ cb(ok);
+ } else {
+ engine->submit_stat(filename, cb);
+ }
+}
+void scan_file_block(const vector<Needle> &needles, string_view compressed,
+ IOUringEngine *engine, AccessRXCache *access_rx_cache, uint64_t seq, ResultReceiver *serializer,
+ atomic<uint64_t> *matched)
+{
unsigned long long uncompressed_len = ZSTD_getFrameContentSize(compressed.data(), compressed.size());
if (uncompressed_len == ZSTD_CONTENTSIZE_UNKNOWN || uncompressed_len == ZSTD_CONTENTSIZE_ERROR) {
fprintf(stderr, "ZSTD_getFrameContentSize() failed\n");
string block;
block.resize(uncompressed_len + 1);
- size_t err = ZSTD_decompress(&block[0], block.size(), compressed.data(),
- compressed.size());
+ static thread_local ZSTD_DCtx *ctx = ZSTD_createDCtx(); // Reused across calls.
+ size_t err;
+
+ if (ddict != nullptr) {
+ err = ZSTD_decompress_usingDDict(ctx, &block[0], block.size(), compressed.data(),
+ compressed.size(), ddict);
+ } else {
+ err = ZSTD_decompressDCtx(ctx, &block[0], block.size(), compressed.data(),
+ compressed.size());
+ }
if (ZSTD_isError(err)) {
fprintf(stderr, "ZSTD_decompress(): %s\n", ZSTD_getErrorName(err));
exit(1);
}
block[block.size() - 1] = '\0';
+ auto test_candidate = [&](const char *filename, uint64_t local_seq, uint64_t next_seq) {
+ access_rx_cache->check_access(filename, /*allow_async=*/true, [matched, engine, serializer, local_seq, next_seq, filename{ strdup(filename) }](bool ok) {
+ stat_if_needed(filename, ok, engine, [matched, serializer, local_seq, next_seq, filename](bool ok) {
+ if (ok) {
+ ++*matched;
+ serializer->print(local_seq, next_seq - local_seq, filename);
+ } else {
+ serializer->print(local_seq, next_seq - local_seq, "");
+ }
+ free(filename);
+ });
+ });
+ };
+
+ // We need to know the next sequence number before inserting into Serializer,
+ // so always buffer one candidate.
+ const char *pending_candidate = nullptr;
+
+ uint64_t local_seq = seq << 32;
for (const char *filename = block.data();
filename != block.data() + block.size();
filename += strlen(filename) + 1) {
+ const char *haystack = filename;
+ if (match_basename) {
+ haystack = strrchr(filename, '/');
+ if (haystack == nullptr) {
+ haystack = filename;
+ } else {
+ ++haystack;
+ }
+ }
+
bool found = true;
- for (const string &needle : needles) {
- if (strstr(filename, needle.c_str()) == nullptr) {
+ for (const Needle &needle : needles) {
+ if (!matches(needle, haystack)) {
found = false;
break;
}
}
- if (found && has_access(filename, access_rx_cache)) {
- ++matched;
- if (print_nul) {
- printf("%s%c", filename, 0);
- } else {
- printf("%s\n", filename);
+ if (found) {
+ if (pending_candidate != nullptr) {
+ test_candidate(pending_candidate, local_seq, local_seq + 1);
+ ++local_seq;
}
+ pending_candidate = filename;
}
}
- return matched;
+ if (pending_candidate == nullptr) {
+ serializer->print(seq << 32, 1ULL << 32, "");
+ } else {
+ test_candidate(pending_candidate, local_seq, (seq + 1) << 32);
+ }
}
-size_t scan_docids(const vector<string> &needles, const vector<uint32_t> &docids, const Corpus &corpus, IOUringEngine *engine)
+size_t scan_docids(const vector<Needle> &needles, const vector<uint32_t> &docids, const Corpus &corpus, IOUringEngine *engine)
{
Serializer docids_in_order;
- unordered_map<string, bool> access_rx_cache;
- size_t matched = 0;
+ AccessRXCache access_rx_cache(engine, corpus.get_hdr().check_visibility);
+ atomic<uint64_t> matched{ 0 };
for (size_t i = 0; i < docids.size(); ++i) {
uint32_t docid = docids[i];
- corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, &docids_in_order](string compressed) {
- docids_in_order.do_or_wait(i, [&matched, &needles, compressed{ move(compressed) }, &access_rx_cache] {
- matched += scan_file_block(needles, compressed, &access_rx_cache);
- });
+ corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, engine, &docids_in_order](string_view compressed) {
+ scan_file_block(needles, compressed, engine, &access_rx_cache, i, &docids_in_order, &matched);
});
}
engine->finish();
return matched;
}
+struct WorkerThread {
+ thread t;
+
+ // We use a result queue instead of synchronizing Serializer,
+ // since a lock on it becomes a huge choke point if there are
+ // lots of threads.
+ mutex result_mu;
+ struct Result {
+ uint64_t seq;
+ uint64_t skip;
+ string msg;
+ };
+ vector<Result> results;
+};
+
+class WorkerThreadReceiver : public ResultReceiver {
+public:
+ WorkerThreadReceiver(WorkerThread *wt)
+ : wt(wt) {}
+
+ void print(uint64_t seq, uint64_t skip, const string msg) override
+ {
+ lock_guard<mutex> lock(wt->result_mu);
+ if (msg.empty() && !wt->results.empty() && wt->results.back().seq + wt->results.back().skip == seq) {
+ wt->results.back().skip += skip;
+ } else {
+ wt->results.emplace_back(WorkerThread::Result{ seq, skip, move(msg) });
+ }
+ }
+
+private:
+ WorkerThread *wt;
+};
+
+void deliver_results(WorkerThread *wt, Serializer *serializer)
+{
+ vector<WorkerThread::Result> results;
+ {
+ lock_guard<mutex> lock(wt->result_mu);
+ results = move(wt->results);
+ }
+ for (const WorkerThread::Result &result : results) {
+ serializer->print(result.seq, result.skip, move(result.msg));
+ }
+}
+
// We do this sequentially, as it's faster than scattering
// a lot of I/O through io_uring and hoping the kernel will
-// coalesce it plus readahead for us.
-void scan_all_docids(const vector<string> &needles, int fd, const Corpus &corpus, IOUringEngine *engine)
+// coalesce it plus readahead for us. Since we assume that
+// we will primarily be CPU-bound, we'll be firing up one
+// worker thread for each spare core (the last one will
+// only be doing I/O). access() is still synchronous.
+uint64_t scan_all_docids(const vector<Needle> &needles, int fd, const Corpus &corpus)
{
- unordered_map<string, bool> access_rx_cache;
+ {
+ const Header &hdr = corpus.get_hdr();
+ if (hdr.zstd_dictionary_length_bytes > 0) {
+ string dictionary;
+ dictionary.resize(hdr.zstd_dictionary_length_bytes);
+ complete_pread(fd, &dictionary[0], hdr.zstd_dictionary_length_bytes, hdr.zstd_dictionary_offset_bytes);
+ ddict = ZSTD_createDDict(dictionary.data(), dictionary.size());
+ }
+ }
+
+ AccessRXCache access_rx_cache(nullptr, corpus.get_hdr().check_visibility);
+ Serializer serializer;
uint32_t num_blocks = corpus.get_num_filename_blocks();
unique_ptr<uint64_t[]> offsets(new uint64_t[num_blocks + 1]);
complete_pread(fd, offsets.get(), (num_blocks + 1) * sizeof(uint64_t), corpus.offset_for_block(0));
+ atomic<uint64_t> matched{ 0 };
+
+ mutex mu;
+ condition_variable queue_added, queue_removed;
+ deque<tuple<int, int, string>> work_queue; // Under mu.
+ bool done = false; // Under mu.
+
+ unsigned num_threads = max<int>(sysconf(_SC_NPROCESSORS_ONLN) - 1, 1);
+ dprintf("Using %u worker threads for linear scan.\n", num_threads);
+ unique_ptr<WorkerThread[]> threads(new WorkerThread[num_threads]);
+ for (unsigned i = 0; i < num_threads; ++i) {
+ threads[i].t = thread([&threads, &mu, &queue_added, &queue_removed, &work_queue, &done, &offsets, &needles, &access_rx_cache, &matched, i] {
+ // regcomp() takes a lock on the regex, so each thread will need its own.
+ const vector<Needle> *use_needles = &needles;
+ vector<Needle> recompiled_needles;
+ if (i != 0 && patterns_are_regex) {
+ recompiled_needles = needles;
+ for (Needle &needle : recompiled_needles) {
+ needle.re = compile_regex(needle.str);
+ }
+ use_needles = &recompiled_needles;
+ }
+
+ WorkerThreadReceiver receiver(&threads[i]);
+ for (;;) {
+ uint32_t io_docid, last_docid;
+ string compressed;
+
+ {
+ unique_lock lock(mu);
+ queue_added.wait(lock, [&work_queue, &done] { return !work_queue.empty() || done; });
+ if (done && work_queue.empty()) {
+ return;
+ }
+ tie(io_docid, last_docid, compressed) = move(work_queue.front());
+ work_queue.pop_front();
+ queue_removed.notify_all();
+ }
+
+ for (uint32_t docid = io_docid; docid < last_docid; ++docid) {
+ size_t relative_offset = offsets[docid] - offsets[io_docid];
+ size_t len = offsets[docid + 1] - offsets[docid];
+ // IOUringEngine isn't thread-safe, so we do any needed stat()s synchronously (nullptr engine).
+ scan_file_block(*use_needles, { &compressed[relative_offset], len }, /*engine=*/nullptr, &access_rx_cache, docid, &receiver, &matched);
+ }
+ }
+ });
+ }
+
string compressed;
for (uint32_t io_docid = 0; io_docid < num_blocks; io_docid += 32) {
uint32_t last_docid = std::min(io_docid + 32, num_blocks);
}
complete_pread(fd, &compressed[0], io_len, offsets[io_docid]);
- for (uint32_t docid = io_docid; docid < last_docid; ++docid) {
- size_t relative_offset = offsets[docid] - offsets[io_docid];
- size_t len = offsets[docid + 1] - offsets[docid];
- scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache);
+ {
+ unique_lock lock(mu);
+ queue_removed.wait(lock, [&work_queue] { return work_queue.size() < 256; }); // Allow ~2MB of data queued up.
+ work_queue.emplace_back(io_docid, last_docid, move(compressed));
+ queue_added.notify_one(); // Avoid the thundering herd.
}
+
+ // Pick up some results, so that we are sure that we won't just overload.
+ // (Seemingly, going through all of these causes slowness with many threads,
+ // but taking only one is OK.)
+ unsigned i = io_docid / 32;
+ deliver_results(&threads[i % num_threads], &serializer);
}
+ {
+ lock_guard<mutex> lock(mu);
+ done = true;
+ queue_added.notify_all();
+ }
+ for (unsigned i = 0; i < num_threads; ++i) {
+ threads[i].t.join();
+ deliver_results(&threads[i], &serializer);
+ }
+ return matched;
}
-void do_search_file(const vector<string> &needles, const char *filename)
+// Takes the given posting list, unions it into the parts of the trigram disjunction
+// already read; if the list is complete, intersects with “cur_candidates”.
+//
+// Returns true if the search should be aborted (we are done).
+bool new_posting_list_read(TrigramDisjunction *td, vector<uint32_t> decoded, vector<uint32_t> *cur_candidates, vector<uint32_t> *tmp)
{
- int fd = open(filename, O_RDONLY);
+ if (td->docids.empty()) {
+ td->docids = move(decoded);
+ } else {
+ tmp->clear();
+ set_union(decoded.begin(), decoded.end(), td->docids.begin(), td->docids.end(), back_inserter(*tmp));
+ swap(*tmp, td->docids);
+ }
+ if (--td->remaining_trigrams_to_read > 0) {
+ // Need to wait for more.
+ if (ignore_case) {
+ dprintf(" ... %u reads left in OR group %u (%zu docids in list)\n",
+ td->remaining_trigrams_to_read, td->index, td->docids.size());
+ }
+ return false;
+ }
+ if (cur_candidates->empty()) {
+ if (ignore_case) {
+ dprintf(" ... all reads done for OR group %u (%zu docids)\n",
+ td->index, td->docids.size());
+ }
+ *cur_candidates = move(td->docids);
+ } else {
+ tmp->clear();
+ set_intersection(cur_candidates->begin(), cur_candidates->end(),
+ td->docids.begin(), td->docids.end(),
+ back_inserter(*tmp));
+ swap(*cur_candidates, *tmp);
+ if (ignore_case) {
+ if (cur_candidates->empty()) {
+ dprintf(" ... all reads done for OR group %u (%zu docids), intersected (none left, search is done)\n",
+ td->index, td->docids.size());
+ return true;
+ } else {
+ dprintf(" ... all reads done for OR group %u (%zu docids), intersected (%zu left)\n",
+ td->index, td->docids.size(), cur_candidates->size());
+ }
+ }
+ }
+ return false;
+}
+
+uint64_t do_search_file(const vector<Needle> &needles, const std::string &filename)
+{
+ int fd = open(filename.c_str(), O_RDONLY);
if (fd == -1) {
- perror(filename);
+ perror(filename.c_str());
exit(1);
}
exit(EXIT_FAILURE);
}
- steady_clock::time_point start __attribute__((unused)) = steady_clock::now();
+ start = steady_clock::now();
if (access("/", R_OK | X_OK)) {
// We can't find anything, no need to bother...
- return;
+ return 0;
}
- IOUringEngine engine;
- Corpus corpus(fd, &engine);
+ IOUringEngine engine(/*slop_bytes=*/16); // 16 slop bytes as described in turbopfor.h.
+ Corpus corpus(fd, filename.c_str(), &engine);
dprintf("Corpus init done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
- vector<pair<Trigram, size_t>> trigrams;
- for (const string &needle : needles) {
- if (needle.size() < 3) continue;
- for (size_t i = 0; i < needle.size() - 2; ++i) {
- uint32_t trgm = read_trigram(needle, i);
- corpus.find_trigram(trgm, [trgm, &trigrams](const Trigram *trgmptr, size_t len) {
- if (trgmptr == nullptr) {
- dprintf("trigram %06x isn't found, we abort the search\n", trgm);
- return;
- }
- trigrams.emplace_back(*trgmptr, len);
- });
+ vector<TrigramDisjunction> trigram_groups;
+ if (patterns_are_regex) {
+ // We could parse the regex to find trigrams that have to be there
+ // (there are actually known algorithms to deal with disjunctions
+ // and such, too), but for now, we just go brute force.
+ // Using locate with regexes is pretty niche.
+ } else {
+ for (const Needle &needle : needles) {
+ parse_trigrams(needle.str, ignore_case, &trigram_groups);
}
}
- engine.finish();
- dprintf("Hashtable lookups done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
- if (trigrams.empty()) {
+ unique_sort(
+ &trigram_groups,
+ [](const TrigramDisjunction &a, const TrigramDisjunction &b) { return a.trigram_alternatives < b.trigram_alternatives; },
+ [](const TrigramDisjunction &a, const TrigramDisjunction &b) { return a.trigram_alternatives == b.trigram_alternatives; });
+
+ // Give them names for debugging.
+ unsigned td_index = 0;
+ for (TrigramDisjunction &td : trigram_groups) {
+ td.index = td_index++;
+ }
+
+ // Collect which trigrams we need to look up in the hash table.
+ unordered_map<uint32_t, vector<TrigramDisjunction *>> trigrams_to_lookup;
+ for (TrigramDisjunction &td : trigram_groups) {
+ for (uint32_t trgm : td.trigram_alternatives) {
+ trigrams_to_lookup[trgm].push_back(&td);
+ }
+ }
+ if (trigrams_to_lookup.empty()) {
// Too short for trigram matching. Apply brute force.
// (We could have searched through all trigrams that matched
// the pattern and done a union of them, but that's a lot of
// work for fairly unclear gain.)
- scan_all_docids(needles, fd, corpus, &engine);
- return;
+ uint64_t matched = scan_all_docids(needles, fd, corpus);
+ dprintf("Done in %.1f ms, found %" PRId64 " matches.\n",
+ 1e3 * duration<float>(steady_clock::now() - start).count(), matched);
+ return matched;
}
- sort(trigrams.begin(), trigrams.end());
+
+ // Sneak in fetching the dictionary, if present. It's not necessarily clear
+ // exactly where it would be cheapest to get it, but it needs to be present
+ // before we can decode any of the posting lists. Most likely, it's
+ // in the same filesystem block as the header anyway, so it should be
+ // present in the cache.
{
- auto last = unique(trigrams.begin(), trigrams.end());
- trigrams.erase(last, trigrams.end());
+ const Header &hdr = corpus.get_hdr();
+ if (hdr.zstd_dictionary_length_bytes > 0) {
+ engine.submit_read(fd, hdr.zstd_dictionary_length_bytes, hdr.zstd_dictionary_offset_bytes, [](string_view s) {
+ ddict = ZSTD_createDDict(s.data(), s.size());
+ dprintf("Dictionary initialized after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
+ });
+ }
+ }
+
+ // Look them all up on disk.
+ bool should_early_exit = false;
+ for (auto &[trgm, trigram_groups] : trigrams_to_lookup) {
+ corpus.find_trigram(trgm, [trgm{ trgm }, trigram_groups{ &trigram_groups }, &should_early_exit](const Trigram *trgmptr, size_t len) {
+ if (trgmptr == nullptr) {
+ dprintf("trigram %s isn't found\n", print_trigram(trgm).c_str());
+ for (TrigramDisjunction *td : *trigram_groups) {
+ --td->remaining_trigrams_to_read;
+
+ // If we now know this trigram group doesn't match anything at all,
+ // we can do early exit; however, if we're in a forked child,
+ // that would confuse the parent process (since we don't write
+ // our count to the pipe), so we wait until we're back in to the
+ // regular (non-async) context. This is a fairly rare case anyway,
+ // and the gains from dropping the remaining trigram reads are limited.
+ if (td->remaining_trigrams_to_read == 0 && td->read_trigrams.empty()) {
+ if (in_forked_child) {
+ should_early_exit = true;
+ } else {
+ dprintf("zero matches in %s, so we are done\n", print_td(*td).c_str());
+ if (only_count) {
+ printf("0\n");
+ }
+ exit(1);
+ }
+ }
+ }
+ return;
+ }
+ for (TrigramDisjunction *td : *trigram_groups) {
+ --td->remaining_trigrams_to_read;
+ td->max_num_docids += trgmptr->num_docids;
+ td->read_trigrams.emplace_back(*trgmptr, len);
+ }
+ });
+ }
+ engine.finish();
+ dprintf("Hashtable lookups done after %.1f ms.\n", 1e3 * duration<float>(steady_clock::now() - start).count());
+
+ if (should_early_exit) {
+ return 0;
}
- sort(trigrams.begin(), trigrams.end(),
- [&](const pair<Trigram, size_t> &a, const pair<Trigram, size_t> &b) {
- return a.first.num_docids < b.first.num_docids;
+
+ for (TrigramDisjunction &td : trigram_groups) {
+ // Reset for reads.
+ td.remaining_trigrams_to_read = td.read_trigrams.size();
+
+ if (ignore_case) { // If case-sensitive, they'll all be pretty obvious single-entry groups.
+ dprintf("OR group %u (max_num_docids=%u): %s\n", td.index, td.max_num_docids, print_td(td).c_str());
+ }
+ }
+
+ // TODO: For case-insensitive (ie. more than one alternative in each),
+ // prioritize the ones with fewer seeks?
+ sort(trigram_groups.begin(), trigram_groups.end(),
+ [&](const TrigramDisjunction &a, const TrigramDisjunction &b) {
+ return a.max_num_docids < b.max_num_docids;
});
- vector<uint32_t> in1, in2, out;
+ unordered_map<uint32_t, vector<TrigramDisjunction *>> uses_trigram;
+ for (TrigramDisjunction &td : trigram_groups) {
+ for (uint32_t trgm : td.trigram_alternatives) {
+ uses_trigram[trgm].push_back(&td);
+ }
+ }
+
+ unordered_set<uint32_t> trigrams_submitted_read;
+ vector<uint32_t> cur_candidates, tmp, decoded;
bool done = false;
- for (auto [trgmptr, len] : trigrams) {
- if (!in1.empty() && trgmptr.num_docids > in1.size() * 100) {
- uint32_t trgm __attribute__((unused)) = trgmptr.trgm;
- dprintf("trigram '%c%c%c' (%zu bytes) has %u entries, ignoring the rest (will "
+ for (TrigramDisjunction &td : trigram_groups) {
+ if (!cur_candidates.empty() && td.max_num_docids > cur_candidates.size() * 100) {
+ dprintf("%s has up to %u entries, ignoring the rest (will "
"weed out false positives later)\n",
- trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff,
- len, trgmptr.num_docids);
+ print_td(td).c_str(), td.max_num_docids);
break;
}
- // Only stay a certain amount ahead, so that we don't spend I/O
- // on reading the latter, large posting lists. We are unlikely
- // to need them anyway, even if they should come in first.
- if (engine.get_waiting_reads() >= 5) {
- engine.finish();
- if (done)
- break;
- }
- engine.submit_read(fd, len, trgmptr.offset, [trgmptr, len, &done, &in1, &in2, &out](string s) {
- if (done)
- return;
- uint32_t trgm __attribute__((unused)) = trgmptr.trgm;
- size_t num = trgmptr.num_docids;
- unsigned char *pldata = reinterpret_cast<unsigned char *>(s.data());
- if (in1.empty()) {
- in1.resize(num + 128);
- p4nd1dec128v32(pldata, num, &in1[0]);
- in1.resize(num);
- dprintf("trigram '%c%c%c' (%zu bytes) decoded to %zu entries\n", trgm & 0xff,
- (trgm >> 8) & 0xff, (trgm >> 16) & 0xff, len, num);
- } else {
- if (in2.size() < num + 128) {
- in2.resize(num + 128);
+ for (auto &[trgmptr, len] : td.read_trigrams) {
+ if (trigrams_submitted_read.count(trgmptr.trgm) != 0) {
+ continue;
+ }
+ trigrams_submitted_read.insert(trgmptr.trgm);
+ // Only stay a certain amount ahead, so that we don't spend I/O
+ // on reading the latter, large posting lists. We are unlikely
+ // to need them anyway, even if they should come in first.
+ if (engine.get_waiting_reads() >= 5) {
+ engine.finish();
+ if (done)
+ break;
+ }
+ engine.submit_read(fd, len, trgmptr.offset, [trgmptr{ trgmptr }, len{ len }, &done, &cur_candidates, &tmp, &decoded, &uses_trigram](string_view s) {
+ if (done)
+ return;
+
+ uint32_t trgm = trgmptr.trgm;
+ const unsigned char *pldata = reinterpret_cast<const unsigned char *>(s.data());
+ size_t num = trgmptr.num_docids;
+ decoded.resize(num);
+ decode_pfor_delta1_128(pldata, num, /*interleaved=*/true, &decoded[0]);
+
+ assert(uses_trigram.count(trgm) != 0);
+ bool was_empty = cur_candidates.empty();
+ if (ignore_case) {
+ dprintf("trigram %s (%zu bytes) decoded to %zu entries\n", print_trigram(trgm).c_str(), len, num);
}
- p4nd1dec128v32(pldata, num, &in2[0]);
-
- out.clear();
- set_intersection(in1.begin(), in1.end(), in2.begin(), in2.begin() + num,
- back_inserter(out));
- swap(in1, out);
- dprintf("trigram '%c%c%c' (%zu bytes) decoded to %zu entries, %zu left\n",
- trgm & 0xff, (trgm >> 8) & 0xff, (trgm >> 16) & 0xff,
- len, num, in1.size());
- if (in1.empty()) {
- dprintf("no matches (intersection list is empty)\n");
- done = true;
+
+ for (TrigramDisjunction *td : uses_trigram[trgm]) {
+ done |= new_posting_list_read(td, decoded, &cur_candidates, &tmp);
+ if (done)
+ break;
}
- }
- });
+ if (!ignore_case) {
+ if (was_empty) {
+ dprintf("trigram %s (%zu bytes) decoded to %zu entries\n", print_trigram(trgm).c_str(), len, num);
+ } else if (cur_candidates.empty()) {
+ dprintf("trigram %s (%zu bytes) decoded to %zu entries (none left, search is done)\n", print_trigram(trgm).c_str(), len, num);
+ } else {
+ dprintf("trigram %s (%zu bytes) decoded to %zu entries (%zu left)\n", print_trigram(trgm).c_str(), len, num, cur_candidates.size());
+ }
+ }
+ });
+ }
}
engine.finish();
if (done) {
- return;
+ return 0;
}
dprintf("Intersection done after %.1f ms. Doing final verification and printing:\n",
1e3 * duration<float>(steady_clock::now() - start).count());
- size_t matched __attribute__((unused)) = scan_docids(needles, in1, corpus, &engine);
- dprintf("Done in %.1f ms, found %zu matches.\n",
+ uint64_t matched = scan_docids(needles, cur_candidates, corpus, &engine);
+ dprintf("Done in %.1f ms, found %" PRId64 " matches.\n",
1e3 * duration<float>(steady_clock::now() - start).count(), matched);
+ return matched;
+}
+
+// Run do_search_file() in a child process.
+//
+// The reason for this is that we're not robust against malicious input, so we need
+// to drop privileges after opening the file. (Otherwise, we could fall prey to an attack
+// where a user does locate -d badfile.db:/var/lib/plocate/plocate.db, badfile.db contains
+// a buffer overflow that takes over the process, and then uses the elevated privileges
+// to print out otherwise inaccessible paths.) We solve this by forking and treating the
+// child process as untrusted after it has dropped its privileges (which it does before
+// reading any data from the file); it returns a single 64-bit number over a pipe,
+// and that's it. The parent keeps its privileges, and can then fork out new children
+// without fear of being taken over. (The child keeps stdout for outputting results.)
+//
+// The count is returned over the pipe, because it's needed both for --limit and --count.
+uint64_t do_search_file_in_child(const vector<Needle> &needles, const std::string &filename)
+{
+ int pipefd[2];
+ if (pipe(pipefd) == -1) {
+ perror("pipe");
+ exit(EXIT_FAILURE);
+ }
+
+ pid_t child_pid = fork();
+ switch (child_pid) {
+ case 0: {
+ // Child.
+ close(pipefd[0]);
+ in_forked_child = true;
+ uint64_t matched = do_search_file(needles, filename);
+ int ret;
+ do {
+ ret = write(pipefd[1], &matched, sizeof(matched));
+ } while (ret == -1 && errno == EINTR);
+ if (ret != sizeof(matched)) {
+ perror("write");
+ _exit(EXIT_FAILURE);
+ }
+ fflush(stdout);
+ _exit(EXIT_SUCCESS);
+ }
+ case -1:
+ // Error.
+ perror("fork");
+ exit(EXIT_FAILURE);
+ default:
+ // Parent.
+ close(pipefd[1]);
+ break;
+ }
+
+ // Wait for the child to finish.
+ int wstatus;
+ pid_t err;
+ do {
+ err = waitpid(child_pid, &wstatus, 0);
+ } while (err == -1 && errno == EINTR);
+ if (err == -1) {
+ perror("waitpid");
+ exit(EXIT_FAILURE);
+ }
+ if (WIFEXITED(wstatus)) {
+ if (WEXITSTATUS(wstatus) != 0) {
+ // The child has probably already printed out its error, so just propagate the exit status.
+ exit(WEXITSTATUS(wstatus));
+ }
+ // Success!
+ } else if (!WIFEXITED(wstatus)) {
+ fprintf(stderr, "FATAL: Child died unexpectedly while processing %s\n", filename.c_str());
+ exit(1);
+ }
+
+ // Now get the number of matches from the child.
+ uint64_t matched;
+ int ret;
+ do {
+ ret = read(pipefd[0], &matched, sizeof(matched));
+ } while (ret == -1 && errno == EINTR);
+ if (ret == -1) {
+ perror("read");
+ exit(EXIT_FAILURE);
+ } else if (ret != sizeof(matched)) {
+ fprintf(stderr, "FATAL: Short read through pipe (got %d bytes)\n", ret);
+ exit(EXIT_FAILURE);
+ }
+ close(pipefd[0]);
+ return matched;
+}
+
+// Parses a colon-separated list of strings and appends them onto the given vector.
+// Backslash escapes whatever comes after it.
+void parse_dbpaths(const char *ptr, vector<string> *output)
+{
+ string str;
+ while (*ptr != '\0') {
+ if (*ptr == '\\') {
+ if (ptr[1] == '\0') {
+ fprintf(stderr, "ERROR: Escape character at the end of string\n");
+ exit(EXIT_FAILURE);
+ }
+ // Escape.
+ str.push_back(ptr[1]);
+ ptr += 2;
+ continue;
+ }
+ if (*ptr == ':') {
+ // Separator.
+ output->push_back(move(str));
+ ++ptr;
+ continue;
+ }
+ str.push_back(*ptr++);
+ }
+ output->push_back(move(str));
}
void usage()
{
- // The help text comes from mlocate.
- printf("Usage: plocate [OPTION]... PATTERN...\n");
- printf(" -d, --database DBPATH use DBPATH instead of default database (which is\n");
- printf(" %s)\n", dbpath);
- printf(" -h, --help print this help\n");
- printf(" -0, --null separate entries with NUL on output\n");
+ printf(
+ "Usage: plocate [OPTION]... PATTERN...\n"
+ "\n"
+ " -b, --basename search only the file name portion of path names\n"
+ " -c, --count print number of matches instead of the matches\n"
+ " -d, --database DBPATH search for files in DBPATH\n"
+ " (default is " DBFILE ")\n"
+ " -i, --ignore-case search case-insensitively\n"
+ " -l, --limit LIMIT stop after LIMIT matches\n"
+ " -0, --null delimit matches by NUL instead of newline\n"
+ " -N, --literal do not quote filenames, even if printing to a tty\n"
+ " -r, --regexp interpret patterns as basic regexps (slow)\n"
+ " --regex interpret patterns as extended regexps (slow)\n"
+ " -w, --wholename search the entire path name (default; see -b)\n"
+ " --help print this help\n"
+ " --version print version information\n");
+}
+
+void version()
+{
+ printf("%s %s\n", PACKAGE_NAME, PACKAGE_VERSION);
+ printf("Copyright 2020 Steinar H. Gunderson\n");
+ printf("License GPLv2+: GNU GPL version 2 or later <https://gnu.org/licenses/gpl.html>.\n");
+ printf("This is free software: you are free to change and redistribute it.\n");
+ printf("There is NO WARRANTY, to the extent permitted by law.\n");
+ exit(0);
}
int main(int argc, char **argv)
{
+ vector<string> dbpaths;
+
+ constexpr int EXTENDED_REGEX = 1000;
+ constexpr int FLUSH_CACHE = 1001;
+ constexpr int IGNORE_VISIBILITY = 1002;
static const struct option long_options[] = {
{ "help", no_argument, 0, 'h' },
+ { "count", no_argument, 0, 'c' },
+ { "all", no_argument, 0, 'A' },
+ { "basename", no_argument, 0, 'b' },
{ "database", required_argument, 0, 'd' },
+ { "existing", no_argument, 0, 'e' },
+ { "ignore-case", no_argument, 0, 'i' },
+ { "limit", required_argument, 0, 'l' },
+ { "literal", no_argument, 0, 'N' },
{ "null", no_argument, 0, '0' },
+ { "version", no_argument, 0, 'V' },
+ { "regexp", no_argument, 0, 'r' },
+ { "regex", no_argument, 0, EXTENDED_REGEX },
+ { "wholename", no_argument, 0, 'w' },
+ { "debug", no_argument, 0, 'D' }, // Not documented.
+ // Enable to test cold-cache behavior (except for access()). Not documented.
+ { "flush-cache", no_argument, 0, FLUSH_CACHE },
+ // Mostly useful to dump out the entire database, even if the given directories
+ // are gone. Disables sgid due to security. Not documented.
+ { "ignore-visibility", no_argument, 0, IGNORE_VISIBILITY },
{ 0, 0, 0, 0 }
};
+ setlocale(LC_ALL, "");
for (;;) {
int option_index = 0;
- int c = getopt_long(argc, argv, "d:h0", long_options, &option_index);
+ int c = getopt_long(argc, argv, "Abcd:ehil:n:N0rwVD", long_options, &option_index);
if (c == -1) {
break;
}
switch (c) {
+ case 'A':
+ // Ignored.
+ break;
+ case 'b':
+ match_basename = true;
+ break;
+ case 'c':
+ only_count = true;
+ break;
case 'd':
- dbpath = strdup(optarg);
+ parse_dbpaths(optarg, &dbpaths);
+ break;
+ case 'e':
+ check_existence = true;
break;
case 'h':
usage();
exit(0);
+ case 'i':
+ ignore_case = true;
+ break;
+ case 'l':
+ case 'n':
+ limit_matches = limit_left = atoll(optarg);
+ if (limit_matches <= 0) {
+ fprintf(stderr, "Error: limit must be a strictly positive number.\n");
+ exit(1);
+ }
+ break;
+ case 'N':
+ literal_printing = true;
+ break;
case '0':
print_nul = true;
break;
+ case 'r':
+ patterns_are_regex = true;
+ break;
+ case EXTENDED_REGEX:
+ patterns_are_regex = true;
+ use_extended_regex = true;
+ break;
+ case 'w':
+ match_basename = false; // No-op unless -b is given first.
+ break;
+ case 'D':
+ use_debug = true;
+ break;
+ case FLUSH_CACHE:
+ flush_cache = true;
+ break;
+ case 'V':
+ version();
+ break;
+ case IGNORE_VISIBILITY:
+ ignore_visibility = true;
+ break;
+ default:
+ exit(1);
}
}
- vector<string> needles;
+ if (use_debug || flush_cache || ignore_visibility) {
+ // Debug information would leak information about which files exist,
+ // so drop setgid before we open the file; one would either need to run
+ // as root, or use a locally-built file. Doing the same thing for
+ // flush_cache is mostly paranoia, in an attempt to prevent random users
+ // from making plocate slow for everyone else.
+ // --ignore-visibility is obvious; if we allowed to keep sgid with
+ // that flag on, it would subvert the entire security model.
+ if (setgid(getgid()) != 0) {
+ perror("setgid");
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ if (!print_nul) {
+ stdout_is_tty = isatty(1);
+ }
+
+ vector<Needle> needles;
for (int i = optind; i < argc; ++i) {
- needles.push_back(argv[i]);
+ Needle needle;
+ needle.str = argv[i];
+
+ // See if there are any wildcard characters, which indicates we should treat it
+ // as an (anchored) glob.
+ bool any_wildcard = false;
+ for (size_t i = 0; i < needle.str.size(); i += read_unigram(needle.str, i).second) {
+ if (read_unigram(needle.str, i).first == WILDCARD_UNIGRAM) {
+ any_wildcard = true;
+ break;
+ }
+ }
+
+ if (patterns_are_regex) {
+ needle.type = Needle::REGEX;
+ needle.re = compile_regex(needle.str);
+ } else if (any_wildcard) {
+ needle.type = Needle::GLOB;
+ } else if (ignore_case) {
+ // strcasestr() doesn't handle locales correctly (even though LSB
+ // claims it should), but somehow, fnmatch() does, and it's about
+ // the same speed as using a regex.
+ needle.type = Needle::GLOB;
+ needle.str = "*" + needle.str + "*";
+ } else {
+ needle.type = Needle::STRSTR;
+ needle.str = unescape_glob_to_plain_string(needle.str);
+ }
+ needles.push_back(move(needle));
}
if (needles.empty()) {
fprintf(stderr, "plocate: no pattern to search for specified\n");
- exit(0);
+ exit(1);
+ }
+
+ if (dbpaths.empty()) {
+ // No -d given, so use our default. Note that this happens
+ // even if LOCATE_PATH exists, to match mlocate behavior.
+ dbpaths.push_back(DBFILE);
+ }
+
+ const char *locate_path = getenv("LOCATE_PATH");
+ if (locate_path != nullptr) {
+ parse_dbpaths(locate_path, &dbpaths);
}
- do_search_file(needles, dbpath);
+
+ uint64_t matched = 0;
+ for (size_t i = 0; i < dbpaths.size(); ++i) {
+ uint64_t this_matched;
+ if (i != dbpaths.size() - 1) {
+ this_matched = do_search_file_in_child(needles, dbpaths[i]);
+ } else {
+ this_matched = do_search_file(needles, dbpaths[i]);
+ }
+ matched += this_matched;
+ limit_left -= this_matched;
+ }
+ if (only_count) {
+ printf("%" PRId64 "\n", matched);
+ }
+
+ return matched == 0;
}
projects / plocate / blobdiff